Mass contact between media of different densities

ABSTRACT

A METHOD AND APPARATUS FOR EFFECTING EFFICIENT MASS CONTACT BETWEEN TWO MEDIA OF DIFFERENT DENSITIES IS DISCLOSED. THE ONE OF SAID MEDIA THAT IS OF LESSER DENSITY IS CAUSED TO OBTAIN A VORTICAL FLOW PATTERN BY MEANS OF A CIRCULAR VANED CHAMBER. THE SECOND MEDIUM, THE ONE HAVING THE GREATER DENSITY, IS ENTRAINED IN SAID FLOW PATTERN IN PARTICULATE FORM, AND IS THEREBY CAUSED TO FORM A DENSE CLOUD OF PARTICLES WITHIN SAID VORTICAL FLOW. AN UPPER LIMIT ON PARTICLE SIZE WITHIN THE CLOUD IS ESTABLISHED BY THE DIAMETER OF THE CHAMBER, AND BY AN APERTURED WALL CONSTRUCTION THEREFOR, WHEREBY OVERSIZE PARTICLES ARE CAUSED TO MIGRATE OUTWARDLY FROM THE CHAMBER UNDER THE INFLUENCE OF CENTRIFUGAL FORCE.

March 2; 1971 E. s. YANKURA 3,566,582

MASS CONTACT BETWEEN MEDIA OF DIFFERENT DENSITIES Filed Apri1 4, 1969 4Sheets-Sheet 1 I! w x /X 52-- N I 45 45 53 FIG.

42 45 I 25o s5 L 52 n H 0 if; 45 FIG- 7 53 V FIG. II

I u u 54 V INVENTOR EUGENE S. YANKURA ATTORNEYS FIG. l2

March 2, 1971 E. s. YANKURA 3,556,582

MASS CONTACT BETWEEN MEDIA OF DIFFERENT DENSITIES Filed April 4, 1969 4Sheets-Sheet 2 FIG.9

INVENTOR. EUGENE S. YANKURA ATTORNEYS Mara! 2, 1971 s, YANKURA 3,566,582

MASS CONTACT BETWEEN MEDIA OF DIFFERENT DENSITIES Filed April 4, 1969 4Sheets-Sheet 3 FIG. IO

INVENTOR EUGENE S. YANKURA BY 2%, m a

ATTORNEYS March 2, 1971 3,566,582

MASS CONTACT BETWEEN MEDIA OF DIFFERENT DENSITIES Filed April 4, 1969 E.S. YANKURA 4 Sheets-Sheet &

INVENTOR EUGENE S. YANKURA ,E W BY iaw afl /zw ATTORNEYS United StatesPatent 3,566,582 MASS CONTACT BETWEEN MEDIA OF DIFFERENT DENSITIESEugene S. Yankura, Branford, Conn., assignor to Entoleter, Inc., NewHaven, Conn. Filed Apr. 4, 1969, Ser. No. 813,634 Int. Cl. B01d 47/00US. C]. 55-92 35 Claims ABSTRACT OF THE DISCLOSURE A method andapparatus for effecting efficient mass contact between two media ofdifferent densities is disclosed. The one of said media that is oflesser density is caused to obtain a vortical flow pattern, by means ofa circular vaned chamber. The second medium, the one having the greaterdensity, is entrained in said How pattern in particulate form, and isthereby caused to form a dense cloud of particles within said vorticalflow. An upper limit on particle size within the cloud is established bythe diameter of the chamber, and by an apertured wall constructiontherefor, whereby oversize particles are caused to migrate outwardlyfrom the chamber under the influence of centrifugal force.

The present invention relates to the field of mass contact between twoor more media. Mass contact between a plurality of media is utilized formany purposes, such as to transfer material, or physical or chemicalenergy between the media. These transfer functions are exemplified bysuch illustrations as the scrubbing of dust laden gas by contact withwater, humidifying air by contact with water, distillation of volatilecomponents of a liquid by contact with a gas, heating or cooling a gasby contact with a liquid of higher or lower temperature, and thechemical reaction of a gaseous material with a liquid material bycontact therebetween. In addition to a transfer function, mass contactis also utilized where contact between two media is designed to effectonly a change in one medium, as where one of the media is a catalyst forthe reaction of one or more components in the other medium. Obviously,there are other purposes of mass contact between a plurality of mediathan those illustrations stated, and it is contemplated that the presentinvention may be applicable to many diverse instances where mass contactbetween a plurality of media is desired.

A primary purpose of the present invention is to provide a mode of masscontact between two or more media that is highly efficient, and thatmakes such mode of contact available for purposes for which it hasheretofore not been practical. It is known, for example, to scrub a gasby passing it through a chamber having a water spray, to react a gaswith a liquid by bubbling the gas through the liquid, to distillvolatiles from a liquid by a countercurrent flow of the liquid against agas in a fractionation tower, and to effect catalytic reactions bypassing a gaseous reactant material through a bed of catalytic powder orgranules. All of the foregoing procedures suffer from inefficient masscontact because the area of surface contact between the two media issmall compared with the volumes or masses of the media involved.

In accordance with the present invention, mass contact is effected byestablishing a vortical flow of a fluid medium, and entraining minuteparticles of a second medium in the first medium. For example, the firstmedium may be air, and the second medium may be Water, and the contactmay be for the purpose of scrubbing, humidifying, heating, or coolingthe air. When water is brought into contact with a vortical flow of airof sufficient relative velocity, the water is quickly broken up into afine mist and dispersed in the vortical flow. When the water is suppliedat an adequate rate, the cloud of water particles, or mist, becomesquite densely populated with minute droplets of water, and the cloud issustained by the vortical flow of air, effecting intimate contactbetween the two media. At a selected point in the flow, the two mediaare separated from each other.

In this process, cloud droplets are propelled by forces established bythe vortical air flow, but because of inertia and the relative densitiesof the materials, the air moves at a greater rate than the waterparticles and therefore can be viewed as passing through the cloud ormist. Although the water particles move generally with the vortical airflow, a particle size distribution of droplets tends to develop acrossthe vortex, with the smallest particles seeking the center of thevortex, the largest particles seeking the periphery, and a particle sizegradient between these two extremes. This distribution is effected bythe competing forces of centripetal drag caused by the air flow, andcentrifugal force imparted by the circular motion of the vortex. Eachdroplet seeks the orbit at which the centripetal and centrifugal forcesacting on it are balanced, while working its way axially along the'vortical flow.

In a theoretical system, one might conclude that a droplet of water of agiven size would find its orbit where the centripetal and centrifugalforces are balanced, and then remain in that orbit as it traversedaxially along the vortex. However, the droplets continually change insize. Larger droplets are broken up into smaller ones by collisionbetween droplets and attrition by the air flow, while smaller dropletscombine to form larger ones. These two actions cause a continuousmigration of droplets transversely of the vortex, both inwardly andoutwardly. On statistical average, however, the cloud of droplets tendsto attain a near balance between the centrifugal and centripetal forces,and can be viewed over all as having primarily only a net axial movementalong the vortex.

To attain this condition in practice, one must define the conditions ofoperation so that the vortex has as large a diameter as is required toprovide balanced orbits for the largest droplets encounter, or definethe conditions of operation so that droplets exceeding a given size arepromptly broken up to smaller sizes. Obviously, relatively largedroplets have a relatively small surface to volume ratio, and thereforepresent a relatively inefficient mass contact property. Accordingly, thebasic design of the vortex system is selected to afford a maximum ofsmaller droplet sizes, with the small end of the size distribution beinglimited by the size range at which the droplets would simply be carriedto the eye of the vortex and away with the air flow. It is inefficientand impractical to design the vortex system with a diameter large enoughto accommodate the larger particle sizes. Since the larger particlesizes would be few in number and inefiicient in mass contact, systemsize and energy would be utilized for little purpose. The prevalentapproach utilized by the prior art is to confine the vortex system to adiameter appropriate for the droplet particle size distribution desired,and to confine the larger droplets physically Within the outer perimeterof this diameter until the larger droplets are broken up by the air flowinto the desired size range. This approach results in the consumption ofa disproportionate amount of energy to break up a small percentage ofthe water mass, it burdens an important portion of the vortex systemwith an inefiicient mass contact condition, and it disturbs theparameters of the vortex system that contribute to efficient and stablefunctioning of the smaller droplets size portion of the cloud.

In accordance with the present invention, the problem of oversizedroplet population of the cloud is remedied in a manner entirelydifferently than has heretofore been suggested. In a general sense, theconcept of the present invention is to withdraw and discard .theoversize droplets from the region of vortex operation. In a practicalphysical context, vortical mass contact systems utilize a cylindricalvortex generating chamber. Usually, the circular Wall of the chamber isprovided with louvers oriented to impart a tangential component to theair entering the chamber, and the air exits through a central opening atone end of the cylindrical chamber. Thus, air forced through thischamber is caused to flow in a vortical path, and the water dropletsentrained in this flow are caused to establish the orbiting and axialpattern of movement hereinabove described. In the prevalent priorsystems, the circular wall of the chamber confines the oversize dropletswithin the chamber, and these accumulate adjacent the chamber louveredwall until they are broken into smaller droplets by the incoming air. Asstated above, this operation results in a disproportionate consumptionof energy, and is disruptive to efficient operation of the vorticalsystem with respect to the droplet size range for which the system isdesigned. In systems utilizing the principles of the present invention,the oversize droplets and any resultant accumulation of water along withthe louver wall is caused to pass outwardly of the vortex chamberthrough apertures provided in the chamber wall for this purpose. Whenoperating a vortical mass contact system in accordance with the presentinvention, it will therefore be appreciated that selection of thediameter of the vortex chamber can be used effectively to control thefraction of droplet size range operating in the vortical flow; all otherparameters being constant, a larger diameter functions to enlarge theupper limit of droplet size and a smaller diameter functions to decreaseit, and the vortex system is simply relieved of droplet sizes largerthan the selected size fraction.

The apertures in the vortex chamber wall not only function to relievethe chamber of oversize droplets, but also function to relieve thevortex cloud of any localized excessive accumulation of water.Occasionally, perturbations in the system cause a slugging condition inthe cloud, where a portion of the cloud obtains a higher concentrationof water than another portion of the cloud. The aforementioned aperturesfunction to relieve such concentration differences, and generally can beconsidered to dampen this slugging effect.

It is therefore one object of the present invention to provide forefficient mass contact between two media.

Another object of the present invention is to provide for efiicient masscontact between two media having substantially different densities.

Another object of the present invention is to provide for efficient masscontact between a continuous phase fluid medium and a second medium indiscontinous phase particulate form.

Another object of the present invention is to provide for efficient masscontact between a continuous phase fluid medium and a second medium indiscontinuous phase particulate form, utilizing a vortical flow of thecontinuous phase fluid and suspending particles of the second mediumtherein.

And still another object of the present invention is to provide for thesuspension of particles of a first medium in the vortical flow of asecond medium, and to provide further for the removal of particlesexceeding a selected size from said flow.

Other objects and advantages of the present invention will becomeapparent to those skilled in the art from a consideration of thefollowing detailed description of one exemplary embodiment of theinvention, had in conjunction with the accompanying drawings in whichlike ref- 4 erence characters refer to like or corresponding parts, andwherein:

FIG. 1 is a perspective view of a one-stage embodiment of a mass contactapparatus utilizing the principles of the present invention;

FIG. 2 is a vertical sectional view of the embodiment shown in FIG. 1;

FIG. 3 is a cross-sectional view of said embodiment taken along the line33 of FIG. 2;

FIG. 4 is a cross-sectional view of said embodiment taken along the line4-4- of FIG. 2;

FIG. 5 is a cross-sectional view of said embodiment taken along the line5-5 of FIG. 2;

FIG. 6 is an isolated perspective view of a fragment of a vane assemblyutilized in the practice of the present invention;

FIG. 7 is an enlarged top plan vie-w of the fragment of vane assembly ofFIG. 6;

FIG. 8 is a vertical sectional view of the embodiment schematicallyillustrating the mode of operation of the system;

FIG. 9 is a vertical sectional view of a second embodiment of theinvention, illustrating one form of a two-stage system;

FIG. 10 is a cross-sectional View of the embodiment of FIG. 9, takenalong the line 1010 thereof;

FIG. 11 is an enlarged detailed view of a vane element employed in thepresent embodiments of the invention;

FIG. 12 is an enlarged detailed view of a modified vane element employedin certain forms of the invention; and

FIG. 13 is a vertical sectional view of an additional embodiment of thepresent invention.

To illustrate the present invention, the embodiments shown in theaccompanying drawings are particularly adapted for the scrubbing of dustladen air with Water, for the purpose of removing the dust from the air.However, although described with reference to this use, it is understoodthat the specific embodiment can be applied to other mass contact uses,and in any event, the present invention is not limited to thisparticular embodiment or use, as indicated hereinabove.

FIGS. 1 through 7 illustrate a single stage mass contact system in theform of a gas or air scrubber, which has the following basic units: aninput scroll or volute 21, surrounding a louvered vortex generatingchamber 41, which opens upwardly into an expansion chamber 61, which inturn opens upwardly into a stack 81.

The louvered vortex generating chamber 41 is generally cylindrical inshape, having a closed bottom 42, and a central opening 43 in its upperend. A generally circular louvered wall 44 is formed by a number ofvanes 45 arranged in a circular configuration. The louvered wall 44 isformed only by the vanes 45, with adjacent vanes providing the louveropenings 46 therebetween, and no wall structure other than these vanesis used to define the circular structure of the vortex chamber 41. Atthe top of chamber 41 there is an inwardly extending flange or lip 47,and a second inwardly extending lip is provided by annulus 48. The innerrim of annulus 48 extends farther inwardly of the chamber 41 than doesthe lip 47, although the outer part of annulus 48 overlaps a portion oflip 47. Annulus 48 is spaced upwardly from lip 47 by the mounting posts49. The inner rims of lip 47 and annulus 48 define the opening 43 in theupper end of the cylindrical chamber 4-1.

Input scroll or volute 21 surrounds the cylindrical wall 44 of thevortex chamber 41, and extends the full height of the vortex chamber soas to encompass the entire louver structure thereof. The outer wall 22of the input scroll defines a spiral starting with a zero point at 23and continuing circumambiently around the vortex chamber 41 with acontinuously decreasing radius, until the outer wall 22 attains itsclosest relation to the louver wall 44 when it returns to a point almostcorresponding to the zero point of the scroll.

Opening 43 connects the upper end of the vortex chamber 41 withexpansion chamber 61. Expansion chamber 61 has a cylindrical portion 62that surrounds the opening 43, and has a diameter substantially greaterthan that of the chamber 41, and above the cylindrical portion theexpansion chamber wall tapers inwardly at 63 to connect with stack 81. Afan 82 is located in the stack conduit to draw gas or air into the mouth24 of the scroll 21, through the scroll, through the louver openings 46into the vortex chamber 41, through the opening 43 in the top of thevortex chamber, through the expansion chamber 61, and into the stack 81.

A water inlet pipe 25 enters through the top of the volute 21 at a pointnear its intake mouth 24. A shelf 26 is positioned in the volute 21substantially midway between its top and bottom, and extends completelyaround the circular periphery of the vortex chamber 41. A water drainpipe 26' is located in the bottom wall 27 of the scroll chamber 21 atthe end of the volute, within a water trap formed by the deflector walls28. A second water drain pipe 64 is located in the bottom wall 65 of theexpansion chamber 61.

The basic mode of operation of the mass contact system as thus fardescribed will now be explained, and for this purpose primary attentionis directed to the schematic illustration of FIG. 8. With the fan 82turned on, air is drawn through the mouth 24 of scroll 21, where it isdeflected to a spiral path, and is scooped by vanes 45 into the vortexchamber 41. The combined effect of the scroll and the vanes imparts atangential vector to the air as it is drawn inwardly, and it thereforefollows a vortical path through chamber 41 in the manner generallysuggested by the arrows 51. When the air flow passes lip 47 at the topof chamber 41, it enters the larger diameter chamber 61, where thevortex expands and the linear rate of flow of the air decreases.Thereafter, as the air continues to rise vortically, the flow is againconfined to a smaller diameter, and the air enters the stack 81.

Preferably, the area of the mouth 24 of the scroll 21 is approximatelyequal to the sum of the areas defined by the louver openings 46 betweenthe vanes, and the effect of the scroll is to cause a balanced or equalair flow through the openings 46 for all points around the vortexchamber.

Water is injected into this air flow through inlet pipe 25. Some of thewater is broken up into droplets of various sizes directly by the actionof the gas flow, and some forms a flowing film along the top of shelf 26and along the side wall 22 of the scroll, as indicated at 30. This waterfilm eventually finds its way between the inner edge of the shelf andthe vanes into the lower section of the scroll, where again, some of itis broken up into droplets of various sizes, and some of it accummulateson the bottorn and side wall of the scroll as a flowing film indicatedby numeral 31. When the water film 31 reaches the end of the scroll, itis trapped by deflectors 28 and drained ofl' via pipe 26.

The suspended droplets in the upper and lower sections of scroll 21 areof various sizes, but for illustration, the smaller range of sizes aredenoted by dots 50, and the larger range by small circles 29. Thecentrifugal force of the circular flow causes the larger drops 29 tomove outwardly against the side wall 22, and there join the flowingfilms of water 30 or 31. The smaller size range of droplets 50 arecarried inwardly by the air flow and through the vane openings 46. Someof these droplets may be further reduced in size by reaction with thevanes. These smaller droplets 50 enter the vortical flow of the air inchamber 41, and seek to distribute themselves in size related orbits andmove upwardly through chamber 41, as previously explained. When thedroplets pass lip 47 at the top of chamber 41, they follow the expandinggas vortex and move toward the periphery of the expansion chamber 61. Atthe same time the linear rate of flow of air decreases, so that the drageffect of the air on the droplets is reduced and the droplets of waterfall out and accumulate in the circularly flowing pool 64, which in turnis withdrawn by drain pipe 64. The air, now substantially free of water,continues its flow out the stack 81. The change in direction fromexpansion to contraction of the vortex occasioned by taper 63, furtherdepletes the air of any residual water droplets, by centrifugal action;and the deflector 66 at the top of the chamber 61 further assists inwringing out substantially the last traces of free water from theexiting air.

As previously explained, the air flows through the cloud of droplets,and in this process is brought into intimate and extensive contact withthe water droplets. This is particularly true with the dense mist offine droplets contained in the vortex chamber 41. Accordingly, the dustcontained in the air is collected and removed by the water, the largerdust particles being removed simply by centrifugal action in the scroll21 and collected by the films 30 and 31, and the finer dust particlesbeing collected by the dense mist of fine droplets 50 in the vortexchamber 41. The scrubbing efliciency of the system, of course depends inpart on the ability to sustain a dense mist of droplets whose particlesize range is closely related to that of the dust in the air beingscrubbed. The eflluent water from drains 26' and 64' may, if desired, befiltered or otherwise separated from the dust, and circulated back tothe system through inlet pipe 25.

As explained earlier in this specification, a droplet size gradienttends to become established across the cloud in the vortex chamber 41,with smaller particles traveling in orbits closer to the center of thechamber, and larger droplets traveling in orbits farther from thecenter. Also, as the droplets change size, both increasing anddecreasing, by reaction with the air flow and collision, and as newdroplets seek their appropriate orbits, there is a con tinuous migrationof droplets inwardly and outwardly relative to the center of the chamber41. Through reagglomeration of droplets, a small percentage of dropletsare formed in the vortex cloud whose appropriate orbit, wherecentrifugal and centripetal forces would be balanced under theconditions of air flow established, is at a diameter larger than thataflorded by the louvered wall 44. These droplets are generallyrepresented by the small circles 29 in the chamber 41. These dropletsall migrate to the outer limits of the chamber 41, and in prior artdevices were trapped by the louver wall, and accumulated as a waterfilm, inefficiently consuming energy from the entering air, anddisrupting the maintenance of a uniform regular and dense cloud of finedroplets 50 in the vortex chamber.

In accordance with the present invention these large droplets 29 arepermitted to migrate outwardly through the louver wall 44 into thescroll chamber 21, where they may continue their outward migration tothe scroll wall 22 and join water films 30 or 31; or they be broken upinto smaller droplets by the air flow, and once again carried back intothe vortex chamber 41.

The outward migration of larger droplets of water from the vortexchamber 41 through the louvered wall 44 is permitted by the provision ofapertures in the circular vortex chamber wall. Apertures or slots 52 invanes 45 are provided for this purpose. The migration of the largerdrops 29 from within to outside the vortex chamber, obviously, cannot bein a direction counter to the circular flow of the air. These dropletsmove spirally outwardly through the vortex in a resultant path createdby a tangential flow component in the same direction as the air flow,and a radially outward component. It is apparent therefore, that escapeapertures must be located in a position to receive such droplet flow,and cannot be located in the shadow of an obstruction to that flow,otherwise these escape apertures will not perform their functionefiectively. It will be observed particularly from FIGS. 6

and 7 that the slots 52 are located at a position on their respectivevanes 45 where they can be reached by a spiral outward movement ofdroplets, without obstruction from an upstream vane; and once throughthe aperture, these droplets can continue movement outwardly into thescroll chamber 21 without obstruction from a downstream vane. Obviously,not all of these outwardly migrating oversize droplets arrive at theapertures 52. Some hit non-aperture portions of the vanes and form afilm on the vanes which is broken again into droplets and carried backinto the vortex chamber by the in-rushing air entering between the vanes45. The proportion of aperture to non-aperture area will vary foroptimum operation, depending upon all the other parameters of thesystem.

Each vane 45 is formed with a second aperture 53. This aperture appearsto play little if any role in relieving the vortex chamber of itsoversize water droplets; but rather, it appears that the apertures 53reduce the drag on the air caused by the vanes, by breaking the vacuumthat would otherwise develop on the downstream side of each vane. Ofcourse, both apertures 52 and 53 assist in disintegrating droplets ofwater as they are carried past the vanes through the louver openings 46into the vortex chamber 41.

The presence of shelf 26 vertically dividing the scroll chamber 21 isoptional. With a shallow depth vortex chamber and scroll chamber, thereis no purpose to the shelf, and it is normally omitted. However, whenthe vortex and scroll chambers are deep, the input air is caused toundergo a toroidal twist when deflected in a circular path by the outerscroll wall 22, and this twist affects the vortex generated in thevortex chamber 41, causing uneven distribution of the water dropletscircularly around the cloud, and resulting in irregularities andinefilciencies in operation of the system. The shelf 26 substantiallyeliminates this problem. Obviously, if the depth of the vortex chamberand scroll chamber were increased still further, it would becomeadvantageous to utilize additional spaced shelves in the scroll chamberto divide its depth into more than two levels.

The vortical cloud generated in prior art louvered chambers normally hasa greater annular thickness at its base than at its top, rendering theupper half of the cloud quite inefficient for mass contact purposes.This problem is overcome by an additional feature of the presentinvention. As shown in FIG. 6, each louver vane is skewed along itsvertical axis so that the bottom end 54 is turned to a position morenearly tangent to the vortex chamber circular configuration than is thetop end 55 of the louver vane. A gradual transition between the twopositions is obtained by a twist or skew in the vanes along theirvertical axes.

Because of this relationship, air entering the vortex chamber 41 nearthe bottom has a greater tangential and lesser radial component impartedto it than air entering at the top. Consequently, the eye of thevortical cloud is enlarged at the bottom and reduced at the top,relative to that obtained with straight vertical vanes in the louverwall 44. As a result, the vertical distribution of the vortical cloud,i.e. its radial annular depth and droplet density, is substantiallyuniform along its entire height.

The radial depth of the cloud, or its annular dimension, is controlledin large measure by the inwardly extending lip overhanging the top ofthe vortex chamber, embodied in lip 47 and annulus 48. The innermostextent of the overhang, i.e. the inner circle of annulus 48, essentiallyestablishes the depth of the cloud, at least in the upper region of thevortex chamber 41. In operation, most of the water contained in theVortex cloud rises to the undersurface of the annulus 48, and as thepopulation density of droplets increases at this point, the dropletsagglomerate and form a water film on the under surface of the annulus,and by centrifugal force the water film and droplets are caused to moveoutwardly through the space 56 between the annulus 48 and lip 47 intothe water collection portion of the expansion chamber 61. Some of theair moves in this path through the space 56, but much of it passesupwardly inside the annulus 48, carrying some of the water droplets withit. The air vortex then expands in the expansion chamber 61, carryingthe water droplets over the collection area where they drop out of theair flow as a result of a decreased linear rate of air flow.

The principles of the present invention can be applied to a multistagemass contact system, as Well as the single stage unit above described.Obviously, subsequent stages could be duplicates of the described singlestage, each receiving the effluent air from the expansion chamber of thepreceding stage in a scroll input chamber, to feed a louvered vortexgenerating chamber, and exiting into an expansion chamber. Additionalwater would be mixed with the air in each stage by a water input pipe,such as inlet 25. However, since the air in the expansion chamberalready has a strong circular motion, a scroll input is not necessaryfor stages after the first, and one may employ a stacked second stage asshown in FIGS. 9 and 10.

In these figures, the first stage is identical to that alreadydescribed, and comprises the input scroll chamber 21, the louveredvortex generating chamber 41, and expansion chamber 61. However, in thisinstance, the expansion chamber 61 includes only the cylindrical portion62, the tapered portion 63 being eliminated.

The second stage is stacked on top of the first stage expansion chamber,and it includes an annular input chamber 101, surrounding a louveredvortex generating chamber 111, which has a central top opening feedinginto the expansion chamber 121, and the upper portion of the expansionchamber tapers to connect with a stack 131 containing the fan 141 fordriving the two stage system.

The structure and operation of the vortex generating chamber 111, theexpansion chamber 121, and the stack 131 are substantially identical tothe corresponding units 41, 61, and 81 shown in the one stage system ofFIG. 2, so further description thereof is unnecessary. However, theinput chamber 101 of FIG. 9 is different from the input chamber 21 ofFIG. 2. As previously mentioned, the input chamber 101 is annular with acircular outer wall 102, instead of being a spiral scroll. Further, theair inlet to the input chamber 101 is a louvered bottom wall 103,occupying the entire annular area of the input chamber. This louveredair inlet is formed by a series of vanes 104, with the axis of each vaneoriented radially across the bottom of annular chamber 101, and each isangled upwardly at a pitch between horizontal and vertical. In this way,air drawn through the first stage, enters the second stage indistributed fashion through the louvered inlet bottom wall 103. Inaddition to the circular flow which the air has in the expansion chamber61, further circular energy is imparted to the air by the angle oflouvers 104 as the air is drawn upwardly into the inlet chamber 101 ofthe second stage. This air thus circulates in the inlet chamber 101 andis drawn spirally into the vortex chamber 111 through its louvers 112.The flow oi; air through the vortex chamber 111 and the expansionchamber 121 in the second stage is the same as described above inralation to the corresponding chambers in the first stage.

In addition to a small amount of water droplets carried by the air fromthe expansion chamber of the first stage into the inlet chamber 101 ofthe second stage, water is introduced into the second stage air inletchamber through pipe 105 in the same manner as in the first stage. Thecircular air flow distributes the added water over the bottom 103 of theinlet chamber 101, and the rates of air flow and water feed are selectedso that the upward component of the air flow prevents all but verylittle of this water from descending through the louver bottom 103 intothe first stage. That water that does descend, and is not broken up intodroplets and carried back into the second stage, is collected with thewater accumulation 64 in the first stage expansion chamber and removedby drain 64.

The air flowing into the second stage inlet chamber 101 reacts with thewater accumulated on the louvered bottom 103, to entrain droplets andcarry them into the vortex chamber 111. As a result, a dense cloud ormist of water droplets is established in the vortical flow of chamber111, in the same manner as in the first stage. As the vortical flow ofair and water droplets pass through the vortex chamber, and out the topinto the expansion chamber 121, the water droplets are removed from theentraining air and are collected in the expansion chamber, and thecollected water is removed through the drain 122.

The effect of the second stage is, of course, the same as the firststage, in that it provides for intimate and elficient mass contactbetween the water droplets and the air, to scrub the air and remove dustor other foreign matter therefrom. Also, the structure of the vortexchamber 111 and its apertured vaned louver wall tend to provide asimilar droplet size gradient, and permit the same outward escape of theoversize droplets as in chamber 41, to afford the same dense, uniformand eificient mass contact cloud of droplets.

As herein described, each stage of the multistage system operatessubstantially independently, and the mass contact relationship is alwaysco-current in effect. Instead, it quite apparent that the water drainedfrom outlet 122 from expansion chamber 121 in the second stage of thetwo stage embodiment, can be utilized as the water input feed of thefirst stage through water inlet 25. In this manner, countercurrentoperation would be effected as between the series of stages of amultistage system.

In another modification of the system, it has been found that the watercan be introduced in the center of the vortex chamber adjacent thebottom wall, instead of being introduced into the scroll chamber. Thismodification is illustrated in FIG. 13, where the water input pipe 25'enters the system through the bottom wall 42 of vortex chamber 41, inthe center thereof. A deflector cap 25a is provided over the pipe 25' todirect the water flow outwardly across the bottom wall 42. In thismodification, the film of Water on the bottom of the vortex is driven inan outward spiral path by the air flow in the chamber, and waterdroplets are picked up from this film of Water to form the cloud ofdroplets in the vortex chamber. Any excess Water passes out into the airintake scroll through the apertures in the vortex chamber vanes 45,where some is converted to droplets and entrained in the incoming air,while the remainder fiows into the scroll drain. The cloud formed in thevortex chamber ascends with the vertical air flow, and seeks toestablish the orbital pattern and inward and outward droplet migrationpreviously described. Again, the apertures in vanes 45 relieve thevortex chamber of oversize droplets and excess water in the cloud. Thus,the mass contact system shown in FIG. l3 functions in the same manner asthe previously described embodiment of FIGS. 2 and 9, except for themanner by which one obtains the initial entrainment of water droplets inthe air flow.

When the Water inlet for the system is in the vortex chamber, the reliefof water outwardly from the vortex chamber into the air inlet scroll notonly improves the cloud contact efficiency as previously described, butin addition, the water thus passed outwardly functions to flush thevanes and the air inlet scroll walls clean of accumulated dust andsludge. In the absence of the ability of the vortex chamber to berelieved of some of its water, the air inlet scroll chamber and theouter portions of the vanes would all be dry or only damp, and dust andsludge accumulations would result in blockage and breakdown of thesystem's operation.

In the preceding description, it was pointed out that skewing the vortexchamber vanes along their vertical axes is used to establish asubstantially uniform annular cloud depth along the axis of the vorticalcloud. Appropriate skewing of these vanes can be used for accomplishingother cloud configurations. For example, if one skews these vanesoppositely than as above-described, i.e. to provide a greater radialcomponent to the air flow at the bottom than at the top of the vortexchamber, the vortical cloud can be forced into a configuration where ithas a large annular thickness at the bottom that tapers outwardly toessentially no thickness at the top of the vortex chamber. In thatcircumstance, by the time the droplets in the bottom of the cloud havetraversed to the top, most of them have moved out of the vortex chamberthrough the vane apertures into the inlet scroll chamber. This effectcan be further enhanced by tapering the water relieving vane aperturesso they are larger at the top of the vanes than they are at the bottom,as indicated by aperture slot 52a in vane 45a in FIG. 12.

Utilizing this phenomenon in conjunction with the embodiment shown inFIG. 13, where the water input is had internally of the vortex chamber41', one can establish a large measure of true countercurrent operationwithin a given stage. In this instance, there would be a dominantairflow from the air input scroll 21 radially inward through the vortexchamber 41', and a dominant water droplet fiow from the center of vortexchamber 41' radially outward and into the air input scroll 21'.

Having described in detail one form of the present invention, and havingindicated several modifications thereof, it will be appreciated that thescope of the invention is not limited to the specific systems describedand suggested, nor is the invention limited to operation on anyparticular media. Numerous modifications and variations of the apparatusand method will be apparent to those skilled in the art, and theadaptation of the invention to numerous applications will likewise berecognized. Accordingly, such modifications, variations and adaptationsas are embraced by the spirit and scope of the appended claims arecontemplated as being within the purview of the present invention.

What is claimed is:

1. A method of effecting mass contact between a first material incontinuous phase and a second material in discontinuous phaseparticulate form having a substantially greater density than said firstmaterial, comprising feeding said first material into a generallycylindrical chamber having a louvered wall of substantially circularoverall configuration with louver surfaces oriented at an angle betweenorthogonal and tangent to said circular confiuration, said chamberhaving an exit port at one end, said first material being fed into saidchamber through said louvered wall and being caused by said louversurfaces to flow spirally in said chamber to said exit port, entrainingsaid second material in said flow of said first material, wherebycentrifugal and centripetal forces are imparted to the particles of saidsecond material in said chamber, and increasing the net averagecentripetal force of said entrained particles by removing particles ofsaid second material having a high net centrifugal force outwardly fromsaid chamber through said louvred wall.

2.. A method as set forth in claim 1 wherein the ratio of thecentripetal vector to tangential vector in the flow of said firstmaterial on entering said chamber through said louvered wall isdifferent at different positions along the axis of said chamber.

3. A method as set forth in claim 2, wherein said ratio is greater atthe end of said chamber adjacent said exit port than at the opposite endof said chamber.

4. A method as set forth in claim 2, wherein said ratio is greatest atthe end of said chamber adjacent said exit port and smallest at theopposite end of said chamber, and the transition between said two ratiosis continuous and gradual.

5. A method as set forth in claim 2, wherein said ratio is smaller atthe end of said chamber adjacent said exit port than at the opposite endof said chamber.

6. A method as set forth in claim 2, wherein said ratio is smallest atthe end of said chamber adjacent said exit port and largest at theopposite end of said chamber, and the transition between said two ratiosis continuous and gradual.

7. A method as set forth in claim 1, wherein said second material isintroduced into the flow of said first material outside said chamber.

8. A method as set forth in claim 1, wherein said second material isintroduced into the flow of said first material inside said chamber.

9. A method of effecting mass contact between a first material incontinuous phase and a second material in discontinuous phaseparticulate form having a substantially greater density than said firstmaterial, comprising feeding said first material into a generallycylindrical chamber having a louvered wall of substantially circularoverall configuration with louver vanes oriented at an angle betweenorthogonal and tangent to said circular configuration, said chamberhaving an exit port at one end, and said vanes having aperturestherethrough, said first material being fed into said chamber throughsaid louvered wall and being caused by said vanes to flow spirally insaid chamber to said exit port, entraining said second material in saidflow of said first material, whereby centrifugal and centripetal forcesare imparted to the particles of said second material in said chamber,and relieving the chamber of particles of said second material having ahigh net centrifugal vector force by passage thereof from the interiorto the exterior of said chamber through said apertures in said vanes.

10. A method as set forth in claim 9, wherein the ratio of thecentripetal vector to tangential vector in the flow of said firstmaterial on entering said chamber through said louvered wall isdifferent at different positions along the axis of said chamber.

11. A method as set forth in claim 10, wherein said ratio is greater atthe end of said chamber adjacent said exit port than at the opposite endof said chamber.

12. A method as set forth in claim 10, wherein said ratio is greatest atthe end of said chamber adjacent said exit port and smallest at theopposite end of said chamber, and the transition between said two ratiosis continuous and gradual.

13. A method as set forth in claim 10, wherein said ratio is smaller atthe end of said chamber adjacent said exit port than at the opposite endof said chamber.

14. A method as set forth in claim 10, wherein said ratio is smallest atthe end of said chamber adjacent said exit port and largest at theopposite end of said chamber, and the transition between said two ratiosis continuous and gradual.

15. A method as set forth in claim 9, wherein said second material isintroduced into the flow of said first material outside said chamber.

16. A method as set forth in claim 9, wherein said second material isintroduced into the flow of said first material inside said chamber.

17. A method of effecting mass contact between a first material incontinuous phase and a second material in discontinuous phaseparticulate form having a substantially greater density than said firstmaterial, comprising feeding said first material into a generallycylindrical chamber having a louvered wall of substantially circularoverall configuration with louver vanes oriented at an angle betweenorthogonal and tangent to said circular configuration, said chamberhaving an exit port at one end, and said vanes having aperturestherethrough, said first material being fed into said chamber throughsaid louvered wall and being caused by said vanes to flow spirally insaid chamber to said exit port, entraining said second material in saidflow of said first material, whereby centrifugal and centripetal forcesare imparted to the particles of said second material in said chamber,relieving the chamber of particles of said second material having a highnet centrifugal vector force by passage thereof from the interior to theexterior of said chamber through said apertures in said vanes, andincreasing the average ratio of centrifugal force to centripetal forceimparted to the particles of said second material as they traverseaxially along said chamber toward said exit port, whereby much of saidentrained second material is caused to pass outwardly of said chamberthrough said apertures before reaching said exit port.

18. A method as set forth in claim 17, wherein the area of the aperturesin said vanes is larger at the ends of said vanes adjacent said exitport of said chamber than at the opposite ends.

19. A mass contact apparatus, comprising a substantially cylindricalchamber having a peripheral louvered wall of substantially circularoverall configuration and having louver vanes oriented at an anglebetween orthogonal and tangent to said circular configuration andextending axially of said chamber, said vanes having aperturestherethrough, whereby particles of a circulating mass of materialcontained in said chamber having a high net centrifugal vector force canescape from the interior of said chamber to the exterior thereof throughsaid apertures.

20. A mass contact apparatus as set forth in claim 19, wherein saidangle is different at different positions axially of said chamber.

21. A mass contact apparatus as set forth in claim 19, and furtherincluding a spiral input scroll surrounding said chamber.

22. A mass contact apparatus as set forth in claim 21, wherein saidchamber is substantially closed at one end and has an opening at theother end, and further including an annular member overlying a portionof said opening and being spaced from said opening outwardly of saidchamber.

23. A mass contact apparatus as set forth in claim 22, and furtherincluding a second chamber having a substantially cylindrical portionwith a larger diameter than the first mentioned chamber and overlyingthe first mentioned chamber adjacent said opening, and said secondchamber having an inwardly tapering substantially conical portionoverlying said substantially cylindrical portion.

24. A mass contact apparatus as set forth in claim 19, wherein saidchamber is substantially closed at one end and has an opening at theother end, and further including an annular member overlying a portionof said opening and being spaced from said opening outwardly of saidchamber.

25. A mass contact apparatus as set forth in claim 24, and furtherincluding a second chamber having a substantially closed at one end andsubstantially open at the first mentioned chamber and overlying thefirst mentioned chamber adjacent said opening, and said second chamberhaving an inwardly tapering substantially conical portion overlying saidsubstantially cylindrical portion.

26. A multi-stage mass contact apparatus comprising two substantiallycylindrical chambers, each being substantially closed at one end andsubstatnially open at the opposite end, each having a peripherallouvered wall of substantially circular overall configuration and havinglouver vanes oriented at an angle between orthogonal and tangent to saidcircular configuration and extending axially of said chamber, said vaneshaving apertures therethrough, whereby particles of a circulating massof material contained in either of said chambers having a high netcentrifugal vector force can escape from the interior of the respectivechamber to the exterior thereof through said apertures, said two vanedchambers being positioned in substantially axially aligned and spacedrelation to each other with the closed end of one adjacent the open endof the other, an intermediate chamber interposed between said two vanedchambers and interconnecting them and being substantially cylindrical inoverall configuration and having a diameter larger than said two vanedchambers, a substantially annular input chamber surrounding the louveredwall of said one chamber, and a substantially circular louvered wallcommon between said input chamber and said intermediate chamber for thefiow of material therebetween.

27. A multi-stage mass contact apparatus as set forth in claim 26, andfurther including a spiral scroll input chamber surrounding the louveredwall of said other vaned chamber.

28. A multi-stage mass contact apparatus as set forth in claim 27, andfurther including an additional chamber having a substantiallycylindrical portion with a larger diameter than said one vaned chamberadjacent the open end of said one vaned chamber, and said additionalchamber having an inwardly tapering substantially conical portionadjacent said substantially cylindrical portion remote from said onevaned chamber.

29. A multistage mass contact apparatus as set forth in claim 26, andfurther including an additional chamber having a substantiallycylindrical portion with a larger diameter than said one vaned chamberadjacent the open end of said one vaned chamber, and said additionalchamber having an inwardly tapering substantially conical portionadjacent said substantially cylindrical portion re mote from said onevaned chamber.

30. A method of effecting mass contact between a first material incontinuous phase and a second material in discontinuous phaseparticulate form having a substantially greater density than said firstmaterial, comprising feeding said first material into a generallycylindrical chamber having a louvered wall of substantially circularoverall configuration with louver vanes oriented at an angle betweenorthogonal and tangent to said circular configuration to provide louveropenings in said wall, said chamber having an exit port at one end, andsaid wall having additional apertures therethrough, said first materialbeing fed into said chamber through said louver openings and beingcaused by said vanes to flow spirally in said chamber to said exit port,entraining said second material in said flow of said first material andimparting by said spiral flow centrifugal and centripetal forces to theparticles of said second material in said chamber to cause saidparticles to seek circulating orbits in said chamber where saidcentrifugal and centripetal forces are substantially equal, andrelieving the chamber of particles of said second material having acentrifugal force re quiring a said circulating orbit outside saidchamber by passage thereof from the interior to the exterior of saidchamber through said additional apertures in said vanes.

31. A method of eifecting mass contact between a first material incontinuous phase and second material in discontinuous phase particulateform having a substantially greater density than said first material,comprising establishing an inwardly spiralling vortical fiow of saidfirst material, passing said flow through an apertured circumambientWall surrounding the center axis of said vortical flow, entraining saidsecond material in said How whereby centrifugal and centripetal forcesare imparted to the entrained particles of said second material toestablish a suspension thereof within the confines of said wall, andincreasing the net average centripetal force of said entrained particlescontained in the suspension within the confines of said wall by removingtherefrom suspended particles having a high net centrifugal force bymovement of such suspended particles outwardly from said axis throughthe apertures in said wall.

32. A method as set forth in claim 31, wherein combined tangential andinward radial fiow vectors relative to a circle about said axis areimparted to the fiow of said first material by said apertured wall.

33. A method as set forth in claim 32, wherein combined tangential andinward radial flow vectors relative to a circle about said axis are alsoimparted to the flow of said first material outside the confines of saidapertured wall.

34. A method as set forth in claim 31, wherein combined tangential andinward radial flow vectors relative to a circle about said axis areimparted to the flow of said first material outside the confines of saidapertured wall.

35. A method as set forth in claim 31, wherein at least a portion of theparticles removed outwardly through said apertures are suspendedagglomerates of smaller particles previously entrained in said fiowwithin the confines of said wall.

References Cited UNITED STATES PATENTS 2,756,976 7/1956 Jalma261--79(.1)X 2,817,415 12/1957 Sykes --236X 2,864,463 12/1958 Campbell55-455X 3,128,320 4/1964 Umbricht 55-238X 3,175,340 3/1965 Schulze 55-863,324,634 6/1967 Brahler et al 55-455X 3,299,621 1/1967 Panzica et al.55223 3,331,194 7/1967 Reed et al 26179(.1)X

DENNIS E. TALBERT, 111., Primary Examiner US. Cl. X.R.

23-2, 288; 34-l0, 11, 57, 58; 5594, 223, 228, 236, 238, 241, 257, 26 1,345, 394, 455; 1653, 60; 20l41; 202158; 26l79

